This project proposed to investigate several aspects of the involvement of birds in natural cycles of arboviruses. The most important was to determine the biological capacity of migratory birds to have acted as intercontinental carriers of the equine virulent strain of VE virus into Central America in 1969. During April and early May 1973, and 1974, migratory birds were captured alive at sites on the Pacific lowlands of Guatemala near the epicenter of the explosive 1969 epizootic and epidemic of Venezuelan encephalitis (VE) virus. 11/11 wild caught migrant birds (five species, mostly shorebirds) inoculated with VE virus, 24 hours post inoculation, had mean viremia titers of greater than 10 to the 4.5 power SMicLD50/ml with a maximum titer of 10 to the 8.8 power. At 48 hours 8 of 12 had titers of 3.0, 3.2 and 5.2. Viremia was not detected in bloods of 8 individuals bled on day 4. Based on results the emphasis during the 1974 spring migrating period was placed on enlarging the series of shorebirds, both in numbers and species included. A total of 47 individuals of 10 species of migrating birds were bled on two or more days post inoculation.